Level 66 Pick up the bucket. Move the barrel and pick up the gun. Use the gun to shoot the left horn off of the skull. Pick up the horn. Place the horn in the red box to make a lever, then place the bucket on it. Pick up the 3 rocks and place them into the bucket.
100 Doors 2 Level 67 Walkthrough:
Level 67 Pick up the box on the ground and put it into the stereo. Shake your phone to make the zombie fall.
100 Doors 2 Level 68 Walkthrough:
Level 68 Pick up the crowbar. Repeatedly tap the aliens until they disappear. Make sure to get the one hidden behind the chair.
100 Doors 2 Level 69 Walkthrough:
Level 69 Pick up the deflated balloon on the ground and place it on the helium tank. Pick up the string and hook in the box. Tap the balloon to inflate it. Use the string on it, then the hook on the bottom of that. Drag the balloon string+hook all the way down into the hole and let go. You will see the keys on the hook. Take the keys and use it on the door.
100 Doors 2 Level 70 Walkthrough:
Level 70 Turn off the gravity, then drag the table to the left. Turn on the gravity. Press the red square button on the ground, then drag the table all the way to the right. Turn off the gravity and turn it back on. You will see the key in the broken pieces.